This project aims to: 1) Develop a technic of refluxing blood into a segment of Schlemm's canal so that the degree of patency of the canal may be observed. 2) Continue study on the scleral spur, a structure probably intimately involved in aqueous humor drainage, and 3) Develop a method of low-pressure tonography to be a better diagnostic tool in glaucoma by avoiding the aqueous outflow channel distortion present in current tonography.